JP2582982B2 - Method of detecting message identifier in data transmission network of elevator system - Google Patents

Abstract

Procedure for determining the message identifiers in a CAN data transmission network of an elevator system where message identifiers are used in the transmission of messages. A node (2-6) monitors the data transmissions taking place in the network and stores the other message identifiers in use in the network. When selecting a message identifier, the node makes use of a random number to select an identifier in an identifier table. <IMAGE>

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for detecting a message identifier in a data transmission network of an elevator system.

[0002]

2. Description of the Related Art A data transmission network of an elevator system includes a bus, a control computer connected to the bus, a call button on each floor, a floor call button in an elevator box, and an actuator such as a door motor controller. They form the nodes of the network. In a CAN (Control Area Network) network, the speed characteristics make the parts well suited for use in elevator systems, but the message identifier is used by the transmitting node when transmitting a message. Here, the node identifier of the normal local network (CAN
Network message identifier).

In the current technology, the message identifier is set by a separate set switch located at the node, the fixed message identifier is programmed separately at each node, or the identifier is stored in a separate tool. Is set on each node using. The use of set switches makes nodes more expensive and
And make its installation more difficult. If a fixedly programmed identifier is used, each node becomes a unit with individual characteristics. This can make them difficult to manufacture and difficult to obtain their spare parts. The use of a separate tool is not only time consuming, requires the use of that tool, and the risk of incorrect configuration is inevitable.

An object of the present invention is to provide a method for detecting a message identifier in a data transmission network of an elevator system, which solves the above-mentioned problems of the prior art.

[0005]

According to the present invention, a node selects one of the available message identifiers without requiring a separate configuration, as described later in the claims. .

[0006] Further, the method of the present invention can prevent a setting error caused by connecting equipment. In addition, it provides a simple way of installing nodes. Also, for example, the node itself is inexpensive because a separate switch for setting the message identifier is not required.

Further, since the nodes are sufficiently identical and include software, it is possible to easily produce a node designed to have the same function. The method can also detect incorrect or identical floor number settings. Similarly, the method can place sufficiently identical nodes (eg, floor call buttons) on the same network.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for detecting a message identifier in a data transmission network of an elevator system according to the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 shows a schematic configuration of a CAN data transmission network in an elevator system. In addition to the bus 1 and a control computer (not shown), each node of the network has call buttons 2,3 located at the same level, a floor call button 4 in the elevator car, a floor and direction indicator 5, a door motor. (M) A control unit 6 is provided. In practice, for example, a floor call button would be required for each floor, and their number would be greater than shown in FIG.

In the method of this embodiment, each node 2-6 connected to the network monitors all transmissions in the network and records all messages detected thereby. Nodes select their message identifiers from those not known in the network, for example by using random numbers with values from a free running counter, according to the method described below. When an identifier is selected for its own node, the node adds a random number to the message and sends it as a request signal to the network. The reason for adding a random number to the message is to allow the other nodes to select the same message identifier by chance and to transmit the same message simultaneously to the network as a request signal, so that it is possible to detect a collision between those messages. This is because in a CAN network, a collision of two identical messages transmitted simultaneously is not detected.

[0010] If the messages are transmitted without collision, the transmitting nodes wait a minimum amount of time plus a random delay that all other nodes can respond to even if they select the same identifier. If the node receives a response from the network that it cannot receive the identifier, or if there is a collision during its transmission, it restarts the selection process and the previously used identifier is used. , Or as requested by another node in its response. The state in the case of a collision is "in use", otherwise it is indicated by a response message.

There are three levels of request messages ("request", "busy", and "use"). Each node transmits a "not accept" message if the message received from the network is at a lower level or the same level as that of its own node. Here, "in use" means that the node intends to use the corresponding identifier.

Normal operation of a node begins after the node has successfully transmitted a "use" level message to the network and has been accepted by another node. During this normal operation, a node monitors transmissions in the network as far as its message identifier is concerned, and if it detects that another node is going to use the same identifier, it sends a message containing the status of its own identifier. Send "Not accepted".

In the starting state, some message identifiers remain in the "requesting" or "busy" state of other nodes. For this reason, there must be a device to return such a message identifier to a completely free state.
This is to ensure that free identifiers can be found somewhere, even when almost all identifiers are already in use. This can be performed, for example, by a device that, if the identifier has one of the states of the above-mentioned counter, decrements the counter associated with that state until it returns to the free state.

FIG. 2 shows the software of the node of the present invention in the form of an SA diagram, and the operation will be described below. As shown, between the block 21 representing the identifier selected by the node and the network and the system environment block 22, “timer 2 value” is marked as an arrow from the system environment to the selection process, and The "signal" is also indicated by a broken arrow. in addition,
Dashed arrows "timer stop", "timer start" shown in FIG.
The start of "Timer 2" is described in the direction from the selection process to the system environment side. The dashed arrows drawn from the CAN chip 23 toward the selection process are “collision” and “bus free”, and the opposite direction is the arrow “initialization CA”.
N "and the dashed arrow" Reset CAN ". The arrows from the selection process to the other nodes 24 are the so-called three request message levels and the "not accepted" message, and the response message is shown as transmission from the other node in the opposite direction.

FIG. 3 shows a more detailed diagram of the process of selectively identifying a network and a node. It includes an identification selection step 31 and a confirmation step 32. In addition, FIG. 3 comprises a table 33 of identifiers used in the network, including free identifiers and identifiers already in use. The above messages are linked as shown in FIG. 3, which is described next. The identifier selecting step outputs a timer stop and start, a timer 2 start, a network initialization and a reset signal. In addition, the identifier selection step outputs the above-mentioned level message and its own message identifier to the confirmation step 32. Input signals to the identifier selection step are a timeout signal, the value of timer 2 and bus free, as well as a cancel and collision signal from the confirmation step 32. Selection process and confirmation process are identification tables
Linked at 33, the flow of information from the confirmation step to the table is represented as shown, and similarly the reverse from the selection step to the table.

A selection step 31 selects a message identifier using the table and the random number. The random number is also used based on transmission delay to avoid collisions, which are also sent to the network to verify collisions due to the same identifier being transmitted simultaneously. Confirmation step 32 receives all messages and updates the table with the requested and used identifiers. It also sends a cancel message to the selection process if the same identifier is detected in the network, which sets the requested but unused table identifier to free.

As shown in FIG. 4, the selection step 31 receives a cancel, timeout and bus free message. It sends timer start and stop messages. The value of timer 2 goes through a random number generation 41, which is linked to the selection process, request transmissions 42-44 and new identifier selection 45. The identifier is also input to a selection process linked to a memory 48 containing the selected identifier and a random number. The request transmission and the function of the free identifier 47 are controlled from this memory. In addition, the selection step controls all the sub-steps 41-47 described above, including the reset and initialization CAN chip function 46. In addition, the selection step receives a control signal from the sub-step "use".

As shown in FIG. 5, the identifier selecting step includes "resetting and initializing" the nodes connected to the network.
Activation of the "CAN chip" function and the first timer (Timer 2)
Started by the start of Timer 2 is, for example, a free running counter. When the bus is free (no node to send anything), reading the value of timer 2 generates a random number.

Next, a new identifier selection step is activated, and a new identifier is selected by selecting one of the addresses of the identifier memory determined by the random number. If the identifier is free, the node selects it. After this, the second timer starts and the process waits until a message appears on the network or until the second timer starts working of the monitoring function. A random delay is selected based on a random signal from timer 2 when a message is sent to the network or the start of a time monitor is detected.

After the delay, the first message (request)
Is sent to the network. This message is an identifier,
Consists of a random number and content "Request". The random number is used to identify when two messages are transmitted simultaneously and collide. Because, as described above, even if the identifiers are the same, there is a random number, so that they do not conflict. After this, the process waits the same amount of time as the delay for detecting an identifier already in use. At this stage, the control variable k representing the number of the transmitted "busy" level message is zero.

During the delay (time-out), if no node has responded that the identifier is already in use by another node whose identifier is already in use, a second message (in use) is transmitted to the network. Is done. At the same time, a second timer is started which can send a timeout signal, for example after 250 ms. The second message is transmitted, for example, three times (k <3) if there is no other node that has responded to reserve the corresponding identifier. There is a latency of 250 ms, for example, during this transmission.

Finally, after a fixed delay, a third message (to be used) is transmitted, and after a timeout signal, the program exits the selection process.

If another node secures the appropriate identifier at some stage of the message transmission (the request is at a high level), or if a message collision occurs, the process returns to generating a new random number.

As shown in FIG. 6, the confirmation step 32 controls the message reception 61, the identification table update 62, and the counter 64. The confirmation process receives a timeout and collision signal, as well as an identifier from the message reception. Further, the receiving step is linked to the transmitting and updating steps.

In addition, the confirmation process receives its own node identifier and a request to itself, and it starts a timer,
Outputs timer stop and cancel signals.

As shown in FIG. 7, the identification confirmation step waits for the arrival of a message from another node. When a message arrives, it compares it with the message identifier of its own node. If it is different from the message of its own node, store the state of the message in memory. If the identifier is the same as the message of the own node, the states of the messages are compared with each other. If the message arrived is "not accepted", its status is written to the table, and if it is a "cancel" signal, it is sent to the selection process.

If the arriving message is in the "requesting" state and is the same as the message of the own node, then the message of the own node is not used and is given to another node. Again, if the node's message is a high-level request, it is sent to the network as a "do not accept" message and remains in a waiting state. The same processing is performed at other levels. That is, if the message is at the same level, the node will abandon; if its own message is at a higher level, it will continue to transmit. Each time a node abandons,
It updates the table with the identifiers of the other nodes.

If no collision occurs after transmission of the "not accepted" message, the node starts waiting for a new message. If a collision occurs, the CAN chip is reset and initialized before the start of waiting for a new message. If a timeout occurs while the node is waiting for a message, the node returns to the wait state again, decrementing the identifier counter in the "request" and "busy" states. The underline shown in FIG. 5 and FIG. 7 represents the evacuation condition, and the subsequent operation is shown below the line.

It should be noted that the present invention is not limited to the above-described embodiment, and it is obvious that a person skilled in the art would make changes and additions within the scope of the claims described above within the scope of the present invention. For example, the range of message identifiers in all CAN networks is arbitrary, and in a similar manner one node may select multiple message identifiers for itself.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a data transmission network of an elevator system to which the method of the present invention is applied.

FIG. 2 is a functional block diagram illustrating software connection of nodes of a network according to the embodiment.

FIG. 3 is a functional block diagram showing details of an identifier selecting step in FIG. 2;

FIG. 4 is a functional block diagram showing a link state in an identifier selecting step in FIG. 2;

FIG. 5 is a flowchart illustrating an identifier selection step in the embodiment.

FIG. 6 is a functional block diagram illustrating a link state of a confirmation process according to the embodiment.

FIG. 7 is a flowchart showing a confirmation identifier selecting step in the embodiment.

[Explanation of symbols]

 1 Bus 2,3 call button 4 floor call button 5 floor display and direction indicator 6 door motor controller 21 identifier selection 22 system environment 23 CAN chip 24 other nodes 31 selection process 32 confirmation process 33 identification table 41 random number generation 42 ~ 46 Sub-process

Claims (8)

(57) [Claims] 1. A method for detecting a message identifier in a data transmission network of an elevator system, wherein the message identifier is used for transmitting the message, wherein the node monitors transmission of data occurring in the network, and checks whether other nodes in use in the network. The method of claim 1, wherein the node selects one of the free message identifiers in the data transmission network of the elevator system. 2. The data transmission network of an elevator system according to claim 1, wherein when selecting a message identifier, the node selects the identifier in an identification table or the like by using a random number. Method of detecting message identifier in. 3. The method according to claim 1, wherein the node sends a message containing the selected identifier to the network for checking availability. How to detect the message identifier. 4. The method according to claim 3, wherein in addition to the identifier, the message transmitted by the node comprises a random number. Detection method. 5. The method according to claim 1, wherein if another node has already selected an existing message identifier, the step of identifying the identifier is started again and the selected message identifier is started. A method of detecting a message identifier in a data transmission network of an elevator system, wherein the identifier is recorded as a message identifier of the another node. 6. The method according to claim 1, wherein the message including the message identifier is transmitted as three different levels of messages for checking availability to the network, and each of the nodes comprises: A method for detecting a message identifier in a data transmission network of an elevator system, wherein if an identifier transmitted at a lower level or the same level as that of the node itself is transmitted by another node, it is canceled. 7. The method according to claim 1, wherein the node selects a plurality of message identifiers in the data transmission network of the elevator system. 8. The method according to claim 1, wherein the node starts a normal operation after sending a top-level message to the network and receiving it by another node, The node monitors transmissions in the network during normal operation as far as its message identifier is concerned, and if it detects another node trying to use the same identifier, it will send a cancel message containing the status of its own identifier. A method for detecting a message identifier in a data transmission network of an elevator system, comprising transmitting the message identifier.